Single Bath Sodium Thiosulfate fixing (prints in Amidol)

Hi all:

I've always used ammonium thiosulfate for fixing, but I'm finding that Amidol + rapid fix + certain papers + hot summer darkroom = pink colored prints. With Lodima, by and by, the pink comes out in the wash, with Galerie, not so much. I'd also like to see the true color right away, and the Ammonium fumes are irritating.

Anyway, I need to print today, and don't have time to run all the way to Freestyle Photo to get a second tray for fixing. I will only be using 10-20 sheets total of both chloride and chlorobromide paper today. What should be my procedure for using Sodium Thiosulfate in one tray? Is fixing really as much as 10 minutes? Does more Sod. Th. in the tray help this at all? If it is ten minutes, at what point can I safely turn the lights on to examine the print? 3 minutes? 5 Minutes?

If I use more sheets than expected, at what point should I mix fresh fixer? 15 prints? 20 prints?

After fixing in relatively fresh (<15 prints) Sod. Thio. , am I fine to rinse for 10 minutes before putting the prints in Kodak Selenium? (1+19)

Also, what formula is recommended? I'm considering TF-2 as published in Darkroom Cookbook, 3rd edition. Is there any advantage to adding more thiosulfate? Or does this slow the wash down more?

I'm thinking of the following procedure:

2 min develop, Amidol
30 sec citric acid stop
10 min TF-2 fix
water holding trays, changing water intermittently until finished printing and prints selected
10 min rinse, regular changes of water
3-6 min KRST
5-10 min rinse, regular changes of water
5 min Permawash
30 minutes wash

Sorry for the deluge of questions!
Thanks!

I used TF-2 with amidol developed Azo prints and found it worked well.

Times for sodium-thiosulfate fixers should be 5-10 minutes. Ideally, you would increase fixing time a bit for each print run through the print, the first getting 5 minutes, the last, 10 minutes. If you want to fix to archival or "optimum permanence" standards, then this shouldn't be hard, since your capacity will be low (see below). It's good not to overfix prints, but erring a bit on the side of longer here, especially with a sodium-thiosulfate-based fixer, would seem safest to me.

Is TF-2 alkaline? If so, I'd wait till at least half the fixing time had passed before turning on the white lights to avoid fogging. Carried-over developer gets reactivated in an alkaline environment and turning on the lights before all potentially-exposable silver halides have been converted to insensitive compounds by the fixer can result in fogging/streaking (don't ask how I know this...).

FWIW, you can always fix for five or six minutes, transfer the prints to a holding tray, dump or store the first fix and mix a second and then fix all the prints for another five minutes. Lights can be on in the between time. That way, you'd get the advantage of a second fix.

If you're using one-bath fixation and want "optimum permanence," then you'll find your fixer capacity is pretty low; about 10 8x10s per liter before you should discard and mix more. So-called "commercial" standards are less stringent and you can get 30-40 8x10s per liter. The culprit is the dissolved silver in the fix itself; once it reaches a certain level (0.2-0.5g/liter depending on who you read) then you are no longer getting optimum fixation. Unfortunately, this occurs pretty fast, hence the low capacity numbers. Two-bath fixing solves this problem by keeping the second bath fairly fresh; the majority of fixation and dissolution of silver occurs in the first bath so the levels of dissolved silver in bath two stay low. You can extend "optimum permanence" to 30-40 8x10s per liter of first bath this way.

Best,

Doremus

Thanks, Doremus:

I might mix TF2 without the sodium metaborate, although I still have it stuck in my head that an alkaline fix aids the wash. I wonder if this is really true.

If I do keep it alkaline, would you reckon that I could safely fix 3 minutes, turn on the lights, fix 3 more minutes, transfer to holding trays for up to 3 hours in indoor daylight before a second, fresh fix of 5 minutes?

J

Since you have KRST anyway, why not simply do an archival fixation test? The longer you fix, the longer the required wash might take, even with an alkaline fixer and permawash.

Please do tell how to do said test with KRST. Just put an undiluted drop on a white area and look for a stain after a few minutes? I am doing 8x10 contact sheets, so the prints themselves have no white border. Does the back suffice, or do I wash an unexposed, processed strip along with the prints for this purpose?

Kodak's recommendation for using KRST as a test for residual silver:


Kodak Rapid Selenium Toner 1+9 with water (according to Tech Pub. J-1, 1973, p.41. Undiluted KRST may be better; see below.)
1. Place a drop of the diluted solution on a squeegeed, white margin of a print or a clear part of film.
2. Wait two to three minutes; then wipe off the drop with a clean blotter or cloth. Any discoloration other than a slight cream tint indicates the presence of silver. Refix in fresh fixer.

There is more info at (there was a url link here which no longer exists) where the use of KRST straight instead of diluted is discussed. I use both methods depending on ease of use at the time.

You should also be testing your washing, i.e., doing a residual hypo test. For that, use Kodak's HT-2 formula and the estimator patch, which you can find at
http://unblinkingeye.com/Articles/Archival/archival.html .

I routinely test the last print through a batch of fixer with both tests as a control (it's also the last print into the washer, so gets the shortest wash too).

Best,

Doremus

What Doremus said, plus:

1. you have to do the test on the emulsion side, since only there the selenium toner can react with residual silver halide
2. the stain created by selenium toner is weak, so make sure you do the test in some area that's completely white
3. you don't have to test with a complete sheet of paper, just use a test clip and follow your typical fix&wash procedure, then do the test
4. different papers may require different fixer times, so be prepared to retest if you change paper type

I just printed last night. I think I'm going to switch back to rapid fixer (TF3). For these reasons:

1. The Galerie prints are still being stained in the sodium thiosulfate process. Galerie is therefore completely incompatible with Amidol, at least in my 85 degree summer bathroom darkroom. Maybe I'll try again in winter. Until then, for Galerie, Ansco 130 and rapid fix. The silver chloride prints were perfect for most of the session, then started to get pink on the back later on in the night. Thus any permanent Amidol staining is unrelated to the type of fixer used.

2. After 10 prints, I discarded and freshly mixed the liter of fixer. You have to use so much sodium thiosulfate (250g/L), that the night's session ultimately cost me $8-9 in fixer. Precious Amidol is $6 a session. That seems excessive, as compared to the cost of 200ml/L of ammonium thiosulfate. A gallon of the stuff is $20.

3. There were no obvious fumes, but I still have the slight "darkroom hangover" and my nasal passages are back on the defense. So, no real benefit there. Next time I think I'll mix TF3 without the alkalai and cover the fixer tray with an acrylic panel when it's not in direct use.

4. A ten minute fix instead of a one minute rapid fix cost me well over two additional hours. It was 3am and I was exhausted well before print washing time. I also love the momentum of a quick turnaround between prints. You have time to really react and hone the print, rather than nod off while rocking the fixer tray for half the session.

Are there any benefits I'm missing to Sodium Thiosulfate? I don't see any!

Jarin

Have you tested the prints that turned pink for residual silver. The problem may not be the Amidol but rather incomplete fixing and/or washing. Not only are sodium thiosulfate fixing baths slower in their action but their capacity is significantly less. So it is easy to under fix prints.

I did not test for residual silver, but I only used the liter of fixer for 10 8x10 prints. The pinkness began to appear at around 7 prints. Could there really be excessive silver after only 7 prints? Also, Ammonium Thio. also created pink prints, and from the very first print in the session (although I only fixed for 1 minute, as per Ilford). This is a large part of why I tried the sodium version in the first place.

Jarin Blaschke said:

I did not test for residual silver, but I only used the liter of fixer for 10 8x10 prints. The pinkness began to appear at around 7 prints. Could there really be excessive silver after only 7 prints? Also, Ammonium Thio. also created pink prints, and from the very first print in the session (although I only fixed for 1 minute, as per Ilford). This is a large part of why I tried the sodium version in the first place.

Click to expand...

Ten prints per liter is close to the recommended maximum for this type of fixer which IIRC is 40 8x10 prints per gallon.

Have you tried getting your chemicals from the Chemistry Store? I have found them more reasonable than photochem suppliers. BTW the more chemical you buy at a time the cheaper it gets. The change in price is really quite dramatic.

http://www.chemistrystore.com/Products-Chemicals_A_Z-1.html

Is there a chance, that there is sufficient Amidol carryover in your fixer bath after 7 prints, which cause these pink discolorations? Remember, that Amidol is very active at the pH of TF-2 ...

You could set up a quick test with a thorough water rinse under running water between stop bath and fixer.

Rudeofus said:

Is there a chance, that there is sufficient Amidol carryover in your fixer bath after 7 prints, which cause these pink discolorations? Remember, that Amidol is very active at the pH of TF-2 ...

You could set up a quick test with a thorough water rinse under running water between stop bath and fixer.

Click to expand...

Hmm, good point. I'll try TF-3 without the Metaborate next time. That should help a bit with the Ammonium smell too. I'll let you know how it goes!

J